Acoustic Guitar Humidity Quick Guide

In this quick guide, we’ll discuss the optimal acoustic guitar humidity, the ideal temperature for storing guitars, which humidity levels protect, and those that cause damage. Furthermore, this article will give you a reference list for identifying potential signs of humidification problems with your guitars. Last, we’ll cover a few solutions for humidifying your beloved acoustic instruments. Let’s get into it!

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Understanding Wood Materials

First, you’ll need to keep in mind that any instrument constructed with wood materials, from an acoustic guitar to an oboe, is susceptible to humidification changes, issues, and ultimately damage when not properly maintained. This is true of instruments constructed with solid tonewoods, laminate woods, or both. These changes occur because wood is a porous material. Over time, all wood will absorb moisture and exude moisture based on its relative humidity. As a result, though it does not happen quickly, all wood can shrink and expand depending on the conditions of where the instrument is stored. Those with particularly thin tops such as vintage and luthier-made acoustic guitars are more susceptible to drastic changes and prolonged exposure to poor humidification environments. Thus, they may require more attention than those made with laminate tops or factory-made production guitars that often utilize more wood materials.

Signs of Acoustic Humidity Problems

Though there are many solutions for properly humidifying stringed instruments, having the knowledge to identify an issue without the help of technology is a valuable skill every guitar player should have. It’s also important to note that typically, a combination of these symptoms or one in an extreme manner will be a sign of potential damage. For example, a sharp or muffled-sounding fret here and there, or a small amount of bellying behind the bridge is normal for acoustic guitars and may only require a good setup from your trusted guitar repair expert or luthier. Here are some of the signs of humidity issues and the results when ignored:

Symptoms Of A Dry Guitar (Low Humidity)

  • Flat (♭) Open Strings: (close to a 1/2 step lower)
  • Lower Action: (fret buzzing often results)
  • Shrinking Neck: (multiple sharp frets)
  • Topwood Shrink: (noticeable ridges between woodgrain)
  • Loose Bracing: structural reinforcements begin to separate from tonewoods

Results Of Prolonged Under Humidification (Dry)

  • Side Cracks
  • Back Cracks
  • Top Seam Cracks *most common*
  • Caved-In Top (severe shrinking)
  • Broken Internal Bracing
acoustic-guitar-humidity-damage-bridge-bellying
Bridge Separation
acoustic guitar humidity damage top crack
Top Seam Crack

Symptoms Of A Wet Guitar (High Humidity)

  • Sharp (♯) Open Strings: (close to a 1/2 step higher)
  • Higher Action: (hard to fret individual notes)
  • Rusty Frets & Strings: (oxidation causing rust/fret wear)
  • Topwood Swelling: (noticeable bulge behind the bridge)
  • Lack Of Tone: (soundboard struggles to vibrate & emit sound)

Results of Prolonged Over Humidification (Wet)

  • Bridge Separation From Body
  • Top Seam Cracks *most common*
  • Side Seam Cracks (due to topwood expansion)
  • Tail Block Cracks *common*
  • Extreme fret wear & damage

Summer & Wintertime Guitar Issues

Throughout the seasons, changes in temperature & humidity will affect your acoustic guitars differently. Though the effects of these changes can be mild to drastic depending on your location, the majority of these fluctuations are most likely to occur in the summer and winter months. Factors that will affect the environment where you store your instruments beyond temperature and humidity include how you heat & cool your home, how close you are to a body of water, and most importantly, the relative humidity of your guitar storage space specifically. Whether that’s an entire room, a closet, a travel case, a guitar humidor cabinet, or another storage method, each presents variables that can cause more or less susceptibility with changes in the weather. Lastly, it’s important to note that more often than not, guitar humidity issues present when the instrument has suffered from a lack of humidity (dry) for an extended amount of time, though over-humidification is also possible. Here are the top 3 most common issues players see with their acoustic guitars in winter & summer:

Wintertime Guitar Problems (Low & Dry)

  • Low Action
  • Sharp Frets
  • Small Top Seam Cracks

Summertime Guitar Problems (High & Wet)

  • High Action
  • Oxidized Frets & Strings
  • Extreme Bridge & Top Swelling

The #1 way to avoid damage to your acoustic guitars is to safely preserve them by maintaining the ideal humidity and temperature wherever they’re stored. Here are the numbers you need to know:

  • The ideal temperature for storing & preserving guitars is 70°F
  • 65°F-75°F is a safe temperature range
  • The ideal humidity level for storing & preserving guitars is 45% (relative humidity)
  • 40%-60% RH is a safe humidity range

Acoustic Guitar Humidifier Solutions

Lastly, it’s important to keep in mind that humidity-related issues and the potential damages we’ve discussed so far are preventable when monitored & maintained correctly. Below are three solutions for acoustic guitar humidifiers that will aid in preserving them year-round:

boveda guitar humidifier case american music furniture

Boveda Humidifier Packs For Wood Instruments are a reliable solution for storing guitars in their cases or when traveling. This disposable product maintains a safe 49%RH by automatically adding or removing moisture as needed. However, you will need to keep an accurate hygrometer in the case to monitor the RH regularly and be aware of when the packs need to be replaced. Lastly, the length of time that these (and other) humidity packs last before needing to be replaced will vary based on the ambient humidity wherever they’re stored.

govee small room humidifier review

Many musicians don’t like the eye sore of a stack of travel cases including the inconvenience of constantly fetching guitars when they feel inspired to play. For a guitarist with a small space, a room humidifier is a common solution. Doing so will allow you to display your instruments on a guitar stand or guitar wall hanger for easy access and convenience. However, this method will require regular maintenance and monitoring including refilling and cleaning. Check out our in-depth article on understanding guitar humidification for more info on this option.

guitar case humidifier cabinet display by american music furniture

If you’re looking to avoid daily maintenance, constant monitoring and refilling, and purchasing humidification products, AMF’s handcrafted climate-controlled guitar display cabinets provide the safest environment for humidifying acoustic guitars and other stringed instruments. Whether it’s a cabinet customized for your collection or a humidified acoustic guitar display case for that one special guitar, our guitar humidors and expert design ensure your instruments are preserved and beautifully displayed for life with very little maintenance.

Recap

  • ALL wood is affected by moisture
  • Wood will expand & contract depending on the relative humidity
  • These changes happen slowly over time (as moisture is absorbed & expelled)
  • Know the symptoms of a dry guitar (under-humidified)
  • Know the symptoms of a wet guitar (over-humidified)
  • Know the temperature & RH “safe zones” | (65°F-75°F & 40%-60%RH)
  • Aim for the ideal guitar humidity & temperature | (45%RH at 70°F)
  • Choose a humidifier solution that works best for your lifestyle & budget

American Music Furniture Solutions

In the last decade, AMF has pioneered and continued to lead our industry by providing the premier solution for instrument preservation & display. Our components, cases, and cabinets have been thoroughly tested & approved by both the C. F. Martin & Co. Quality Assurance Team and Hard Rock Cafe, Inc. In addition to C. F. Martin & Co., our other partners include Taylor Guitars, Bourgeois Guitar, George Nakashima Woodworkers, and others. AMF’s handcrafted furniture goes beyond instrument displays including custom built-ins, gear storage, turntable & vinyl storage credenzas, interior design services, and more. Contact us today to get started on your music-inspired design: Call or Text: (267) 272-2460 | Send us an Email